The oxygen sensor installs in the downstream position on 2006-2008 Peugeot 407 with the 2.2L I4 engine. It signals whether the exhaust is running rich or lean so the engine computer can trim fuel delivery. It uses a female rectangle connector with 4 terminals.

Walker Products 250-24921 Oxygen Sensor Features:

• Fits 2006-2008 Peugeot 407 with the 2.2L I4 engine
• Sensor location by application: B1S2 (bank and sensor number)
• 4-wire narrow-band oxygen sensor
• Built-in heater for fast warm-up
• M18x1.5 threaded mounting with a 22 mm hex, 1825 mm (71.9 in.) overall length
• Female rectangle connector at the harness end with 4 spade terminals
• Platinum electrode layer with a protective coating against combustion residue